"Santa Isabel is a small andesitic shield volcano that is dwarfed by its neighbors to the NE (Nevado del Ruiz) and SE (Tolima). Three lava domes occupy the elongated, N-S-trending glaciated summit region, which has two main peaks. Holocene lava flows fill valleys SW and SE of Santa Isabel. A small Holocene lava dome was emplaced at the center of a circular depression about 10 km SW of the volcano. No historical eruptions have occurred from Santa Isabel." -Smithsonian Volcano Archive